The invention relates generally to sprockets used to drive modular plastic conveyor belts and, more particularly, to sprockets molded out of two plastic materials.
Modular plastic conveyor belts are used in a wide range of conveyor applications. Unlike flat belts, which are driven by tensioned rollers or pulleys, modular plastic conveyor belts are driven by sprockets, which positively engage drive structure in the belts. The most common sprockets are molded or machined out of one homogeneous plastic or metal material. The sprocket material is chosen to best match the application. In some instances, the properties of a single material may serve some of the needs of an application well, but may be less than optimum for other needs. For example, in an abrasive environment, a sprocket made entirely of polyurethane, which has good abrasion-resistant properties, may be suggested, but it may be too flexible to drive the belt effectively. As another example, glass-filled materials provide strength and firmness to plastic articles, but are too abrasive in contact with a belt. Thus, there is a need for a sprocket that combines the best properties of various materials to accommodate a wide range of applications.